Design of high-strength backfill for a drift-and-fill mining method at Olympias Mine, Greece

Authors: Grobler, H; Chatziefstratiou, V; Mousli, O; Yumlu, M Download Paper Open access courtesy of:

DOI https://doi.org/10.36487/ACG_rep/1910_28_Grobler

Cite As:
Grobler, H, Chatziefstratiou, V, Mousli, O & Yumlu, M 2019, 'Design of high-strength backfill for a drift-and-fill mining method at Olympias Mine, Greece', in AJC Paterson, AB Fourie & D Reid (eds), Paste 2019: Proceedings of the 22nd International Conference on Paste, Thickened and Filtered Tailings, Australian Centre for Geomechanics, Perth, pp. 401-410, https://doi.org/10.36487/ACG_rep/1910_28_Grobler



Abstract:
Olympias Mine is operated by Hellas Gold S.A., a subsidiary of Eldorado Gold Corporation. The orebody shape and size are suitable for a drift and fill mining method. The mining sequence is overhand and the demand for backfill strengths are generally low except for the initial sill cuts. The design fill strengths are determined from the planned stope exposures to allow for safe extraction of the ore in adjacent drifts and immediately below the initial sill drifts with minimum dilution. Due to the permit constraints imposed on mining at Olympias Mine, after an environmental impact assessment, there is a requirement that the final backfill strength must reach a uniaxial compressive strength (UCS) of 4.0 MPa at 28-day cure age. By developing a suit of mix recipes incorporating superplasticiser admixtures, it was possible to achieve the strength demands and the workability of the backfill. This paper presents the results from comprehensive test work conducted on whole mill tailings and cyclone mill tailings to produce high strength backfill.

Keywords: drift and fill, backfill plant, cemented fill, test work, rheology, yield stress, mix design, reticulation, superplasticisers, admixtures, uniaxial compressive strength

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